Formation and Crystal Structures of 9-Methylanthracene Photodimer and Lepidopterene

The 9-methylanthracene photodimer (6) and lepidopterene (7) were prepared by a photo-dimerisation reaction of 1-(9-anthracenylmethyl)-3-ethylimidazolium iodide (1) or α, α'-di[1-(9-anthracenylmethyl) imidazolium]- p-xylene dibromide (2). Compound 6 is derived from the head-tail [4+4] cycloaddition of two molecular 9-methylanthracenes, and the butterfly-shaped compound 7 is formed via the 9-methyleneanthracene radical in a two steps precess. The single crystal structure of 6 was determined by X-ray diffraction analysis. The changes of luminescent intensities of compounds 1, 2 and 7 are reported.